Lens barrel, lens driving device, and image pickup apparatus

ABSTRACT

A lens barrel that is capable of miniaturizing and thinning an image pickup apparatus by enabling to switch manual lens drive and electric lens drive with a simple mechanism. A lens barrel is mounted on an image pickup apparatus that supports an operation member rotatably. A drive barrel engages with a lens holding member to drive it in an optical axis direction. A motor transfers rotation to the drive barrel through a transfer mechanism. A switching mechanism switches between electric lens drive that drives the lens holding member by transferring rotation of the motor to the drive barrel and manual lens drive that drives the lens holding member by transferring rotation of the operation member to the drive barrel via an elastic member that rotates together with the operation member according to a user&#39;s operation. The drive barrel engages with the elastic member while shifting to a photographing area.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a lens barrel installed in an imagepickup apparatus, such as a digital camera, a digital video camera, andrelates to an image pickup apparatus equipped with the lens barrel.Moreover, the present invention relates to a lens driving device of adigital camera equipped with a zoom lens barrel, and relates to an imagepickup apparatus equipped with the lens driving device.

Description of the Related Art

There are some known image pickup apparatus, such as digital cameras,that enable zooming and focusing by moving lenses in accordance with arotary operation of an operation ring provided on an outside peripheryof a lens barrel. For example, a configuration that enables electriczoom drive and manual zoom drive that are selected using a changeoverswitch provided on a side portion of a lens barrel is disclosed(Japanese Laid-Open Patent Publication (Kokai) No. 2008-58914 (JP2008-58914A), and Japanese Laid-Open Patent Publication (Kokai) No.2006-259130 (JP 2006-259130A)).

Moreover, a configuration that enables an operation with feeling closeto a manual operation by detecting a rotation amount of an operationring and driving a lens electrically corresponding to the detectedrotation amount is disclosed (Japanese Laid-Open Patent Publication(Kokai) No. H5-11163 (JP H5-11163A)). Furthermore, a configuration witha gear mechanism that receives two inputs to a lens barrel is disclosed(Japanese Laid-Open Patent Publication (Kokai) No. 2012-42619 (JP2012-42619A)). The gear mechanism enables zoom drives by manualoperation of an operation ring and by electric drive without providing achangeover switch.

Moreover, Japanese Laid-Open Patent Publication (Kokai) No. 2013-083775(JP 2013-083775A) discloses a technique that transfers rotational forceof a rotary operation of an operation ring to a zoom drive systemthrough a clutch gear when a changeover switch between electric driveand manual drive is switched to the manual drive. This technique needsto operate the operation ring with rotary torque more than detent torqueof a motor.

However, since the configurations in the above-mentioned JP 2008-58914Aand JP 2006-259130A require a gear train that transfers the rotation ofthe operation ring to the lens barrel and the switching mechanism formoving a gear in an axial direction, the number of parts becomes large,which prevents the image pickup apparatus in addition to the lens barrelfrom miniaturizing.

Moreover, since the configuration in the above-mentioned JP H5-11163Aaccumulates an influence of backlash of the switching mechanism to thegear teeth when the rotation of the operation ring is transferred to thelens barrel through the gear train, the effect of shakiness of theswitching mechanism to a gear tooth, time lag may occur between arotary-operation timing of the operation ring and a drive timing of thelens.

Furthermore, although the configuration in the above-mentioned JP2012-42619A solves the problem of the switching mechanism, a large spaceis needed in order to install the gearing mechanism that receives thetwo inputs, which prevents the image pickup apparatus in addition to thelens barrel from miniaturizing and thinning.

Moreover, since the technique in JP 2013-083775A makes the feeling ofthe manual rotary operation of the operation ring heavy because offriction of the gear train including the motor, the operability of theoperation ring drops. And since the clutch gear is needed in the geartrain, the configuration is complicated. Furthermore, when a worm isinstalled between the motor and the gear train, for example, anengagement relation (the number of threads) must be considered in orderto rotate the motor smoothly by transmitting the rotational force of theoperation ring to the motor through the gear train, which restricts thedesign.

SUMMARY OF THE INVENTION

The present invention provides a technique that miniaturizes and thinsan image pickup apparatus in addition to a lens barrel by enabling toswitch manual lens drive and electric lens drive with a simplemechanism, and that prevents time lag from generating between a rotaryoperation of an operation member and lens drive.

Moreover, the present invention provides a technique that enables toswitch an electric operation and a manual operation by the operationmember of the lens barrel with a simple mechanism, and to improveoperability of the manual operation of the operation member.

Accordingly, a first aspect of the present invention provides a lensbarrel mounted on an image pickup apparatus that supports an operationmember rotatably, the lens barrel comprising a drive barrel configuredto engage with a lens holding member that holds a lens and to drive thelens holding member in an optical axis direction by moving in theoptical axis direction while rotating, a motor configured to transferrotation to the drive barrel through a transfer mechanism, and aswitching mechanism configured to switch lens drive between electriclens drive that drives the lens holding member in the optical axisdirection by transferring rotation of the motor to the drive barrel andmanual lens drive that drives the lens holding member in the opticalaxis direction by transferring rotation of the operation member to thedrive barrel via an elastic member that rotates together with theoperation member, according to a user's operation. The drive barrelengages with the elastic member while shifting from a non-photographingarea to a photographing area in the optical axis direction so as toallow the rotation of the operation member to transfer.

Accordingly, a second aspect of the present invention provides an imagepickup apparatus comprising an operation member configured to besupported by the image pickup apparatus so as to allow a rotaryoperation, an elastic member configured to be arranged in an innerperiphery of the operation member, and to rotate together with theoperation member, and the zoom lens barrel of the first aspectconfigured to change photographing magnification by moving a pluralityof lens groups included in an optical axis direction.

Accordingly, a third aspect of the present invention provides a lensdriving device comprising a motor, a gear train configured to transferdriving force of the motor, a drive barrel on which a gear part that isable to mesh with the gear train, that rotates when the driving force ofthe motor is transferred to the gear part via the gear train, and thatmoves a plurality of lens groups in an optical axis direction byrotating, and an operation member that is provided on the circumferenceside of the drive barrel so as to be movable in the optical axisdirection and to allow a rotary operation, and that engages with thedrive barrel in a rotation direction and the optical axis direction soas to be detachable. The drive barrel meshes with the operation memberin the optical axis direction and moves in the optical axis directiontogether with the operation member so that the engagement between thegear part and the gear train is released and the drive barrel engageswith the operation member in the rotation direction and rotates togetherwith the operation member, when the operation member is moved in theoptical axis direction.

Accordingly, a fourth aspect of the present invention provides an imagepickup apparatus equipped with the lens driving device of the thirdaspect.

The first and second aspects of the present invention enable tominiaturize and thin the image pickup apparatus in addition to the lensbarrel by enabling to switch manual lens drive and electric lens drivewith a simple mechanism, and prevent time lag from generating between arotary operation of the operation member and lens drive.

Moreover, the third and fourth aspects of the present invention enableto switch an electric operation and a manual operation by the operationmember of the lens barrel with a simple mechanism, and to improveoperability of the manual operation of the operation member.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view showing a digital camera as an imagepickup apparatus according to a first embodiment of the presentinvention viewed from a front side. FIG. 1B is a perspective viewshowing the digital camera shown in FIG. 1A viewed from a rear side.

FIG. 2 is an exploded perspective view showing the digital camera shownin FIG. 1A.

FIG. 3A is a view of a lens barrel fixed to an inner flame of thedigital camera shown in FIG. 1A viewed from the front side. FIG. 3B is aview of the lens barrel viewed from the front side.

FIG. 4 is a sectional view showing the lens barrel shown in FIG. 3B in acollapsed position.

FIG. 5 is a sectional view showing the lens barrel shown in FIG. 3B in aphotographing position.

FIG. 6 is an exploded perspective view of the lens barrel shown in FIG.3B.

FIG. 7 is a development view showing an inner periphery of a fixed cambarrel in the lens barrel shown in FIG. 3B.

FIG. 8 is a developed view showing an inner periphery of a drive barrelin the lens barrel shown in FIG. 3B.

FIG. 9A is a view describing a transmission path of the driving forcefrom a motor to the driving barrel in the lens barrel shown in FIG. 3B.FIG. 9B is an exploded perspective view of a slip gear shown in FIG. 9A.

FIG. 10A is a sectional view showing a relationship between a gearconnection switching mechanism and the slip gears of the lens barrelshown in FIG. 3B in an electric zoom drive state. FIG. 10B is asectional view showing an idling state of the slip gears shown in FIG.10A. FIG. 10C is a sectional view showing the relationship between thegear connection switching mechanism and the slip gear of the lens barrelshown in FIG. 3B in a manual zoom drive state. FIG. 10D is a sectionalview showing a pressing start state of the slip gear when the manualzoom drive state shown in FIG. 10C is switched to the electric zoomdrive state.

FIG. 11A is an exploded perspective view showing the gear connectionswitching mechanism attached to a gear box of the lens barrel shown inFIG. 3B. FIG. 11B is an exploded perspective view showing a gearenergization unit that constitutes the gear connection switchingmechanism shown in FIG. 11A.

FIG. 12A is a sectional view showing the lens barrel and a zoomoperation ring shown in FIG. 2 in the collapsed position. FIG. 12B is asectional view showing the zoom operation ring and lens barrel shown inFIG. 12A in the photographing position (extended position).

FIG. 13A is a front view describing operations of the gear energizationunit and a regulation shaft when the switching member shown in FIG. 1Ais operated to the electric zoom drive. FIG. 13B is a front viewdescribing operations of the gear energization unit and the regulationshaft when the switching member is operated to the manual zoom drive.

FIG. 14A is a sectional view describing the operations of the gearenergization unit and the regulation shaft when the switching membershown in FIG. 1A is operated to the electric zoom drive. FIG. 14B is asectional view describing the operations of the gear energization unitand the regulation shaft when the switching member is operated to themanual zoom drive.

FIG. 15A is a perspective view describing the actions of the gearenergization unit and the regulation shaft when the switching membershown in FIG. 1A is operated to the electric zoom drive. FIG. 15B is aperspective view describing the operations of the gear energization unitand the regulation shaft when the switching member is operated to themanual zoom drive.

FIG. 16 is a sectional view schematically showing a state where a lensbarrel of a digital camera as a second embodiment of the image pickupapparatus equipped with the lens driving device of the present inventionis in the collapsed position.

FIG. 17 is a sectional view schematically showing a state where the lensbarrel of the digital camera shown in FIG. 16 is in the photographingposition.

FIG. 18 is a sectional view showing an operation ring of the digitalcamera shown in FIG. 16.

FIG. 19 is an exploded perspective view showing the operation ring, adrive barrel, and an outside cover barrel of the digital camera shown inFIG. 16.

FIG. 20A is a developed view showing an outer periphery of the drivebarrel shown in FIG. 19 in a state where power of the camera is OFF andthe lens barrel is in the collapsed position. FIG. 20B is a developedview showing the outer periphery of the drive barrel shown in FIG. 19 ina state where the power of the camera is turned ON and the lens barrelis moved to a wide position.

FIG. 21A and FIG. 21B are developed views showing the outer periphery ofthe drive barrel shown in FIG. 19 in the wide position in states beforeand after the lens barrel is shifted to a manual zoom operation from anelectric zoom operation, FIG. 21C is a developed view showing the outerperiphery of the drive barrel shown in FIG. 19 in a state where the lensbarrel is moved to a telephoto position by the manual zoom operation.

FIG. 22 is a sectional view schematically showing the camera in thestate in FIG. 21A.

FIG. 23 is a sectional view schematically showing the camera in thestate in FIG. 21B.

FIG. 24A and FIG. 24B are developed views showing the outer periphery ofthe drive barrel shown in FIG. 19 in states before and after the lensbarrel is shifted to the electric zoom operation from the manual zoomoperation in the telephoto position,

FIG. 25 is a flowchart describing operations from a power OFF state to aphotographing-ready state in the digital camera shown in FIG. 16.

FIG. 26A and FIG. 26B are flowcharts describing a process for switchingthe zoom operation mode of the digital camera shown in FIG. 16 betweenthe electric zoom operation and the manual zoom operation under thephotographing-ready state.

FIG. 27 is a flowchart describing a process from the photographing-readystate to the power OFF state in the digital camera shown in FIG. 16.

FIG. 28 is a flowchart describing camera operations from the power OFFstate to the photographing-ready state in a digital camera as a thirdembodiment of the image pickup apparatus equipped with the lens drivingdevice of the present invention.

FIG. 29 is a flowchart describing a process from the photographing-readystate to the power OFF state in the digital camera of the thirdembodiment.

DESCRIPTION OF THE EMBODIMENTS

Hereafter, embodiments according to the present invention will bedescribed in detail with reference to the drawings.

FIG. 1A is a perspective view showing a digital camera 1 as an imagepickup apparatus according to a first embodiment of the presentinvention viewed from a front side. FIG. 1B is a perspective viewshowing the digital camera 1 shown in FIG. 1A viewed from a rear side.

As shown in FIG. 1A, the digital camera 1 of the embodiment is providedwith a lens barrel 2 with a zoom lens system that changes photographingmagnification by moving included lenses in an optical axis direction atthe front side. A zoom operation ring 101 is provided around the lensbarrel 2 so as to allow a rotary operation. A switching member 102 thatenables a user to switch a zoom operation mode between electric zoomdrive and manual zoom drive is provided in the vicinity of the zoomoperation ring 101.

Moreover, a power button 103, release button 104, zoom lever 105, modedial 106, exposure correction dial 107, and pop-up flash unit 108 areprovided on an upper side of the digital camera 1. A pop-up lever 109 isprovided on the right side portion of the digital camera 1 viewed fromthe front side. When the pop-up lever 109 is operated, a light emittingsection of the flash unit 108 pops up and the flash unit 108 is readyfor emission.

As shown in FIG. 1B, a display unit 110 that consists of an LCD, amanual operation button group 111, and a gripping part 112 are providedin the back side portion of the digital camera 1. Moreover, a terminalcover 113 that covers a terminal that is used to connect the digitalcamera 1 to an external device is provided on the right side portion ofthe digital camera 1 viewed from the rear side.

FIG. 2 is an exploded perspective view showing the digital camera 1shown in FIG. 1A. As shown in FIG. 2, a battery housing unit 118 isprovided at the left side of the lens barrel 2 viewed from the frontside of the digital camera 1. The flash unit 108 is provided at theright side of the lens barrel 2. The battery housing unit 118 and theflash unit 108 are respectively fixed to an inner flame 114.

The flash unit 108 is provided with a side cover 115 having the pop-uplever 109 that engages with the flash unit 108. A circuit board (notshown) is fixed to the back side of the battery housing unit 118. A CPU,memory, external connection connector, image processing LSI, etc. areimplemented on the circuit board, which is connected to the lens barrel2. Lens groups that constitute a photographing optical system, alens-drive mechanism, and an Image pickup device, such as a CCD sensoror a CMOS sensor, are built into the lens barrel 2.

A front-side cover unit 117 and the zoom operation ring 101 are providedin the front side of the digital camera 1. A ring-shaped elastic member116 made from cushioning material etc. that rotates together with thezoom operation ring 101 is fixed to the inner periphery of the zoomoperation ring 101. The zoom operation ring 101 is supported so as toallow a rotary operation together with the elastic member 116 to thefront-side cover unit 117.

The switching member 102 is attached to the front-side cover unit 117.The switching member 102 is used to switch the manual zoom drive and theelectric zoom drive according to a user's operation, as mentioned above.The position of the switching member 102 is regulated by a switchingmechanism having a click mechanism (not shown) to the front-side coverunit 117. When the front-side cover unit 117 is installed, the switchingmember 102 engages with a gear connection switching mechanism 3.

FIG. 3A is a view of the lens barrel 2 fixed to the inner flame 114viewed from the front side. FIG. 3B is a view of the lens barrel 2viewed from the front side. As shown in FIG. 3A and FIG. 3B, a gear box4 that drives the zooming of the lens barrel 2 is arranged at the lowerright portion of the lens barrel 2. A motor 401 is arranged at thebottom face portion. The gear connection switching mechanism 3 isattached to the upper side of the motor 401.

FIG. 4 is a sectional view showing the lens barrel 2 in a collapsedposition. FIG. 5 is a sectional view of the lens barrel 2 in aphotographing position. FIG. 6 is an exploded perspective view of thelens barrel 2.

As shown in FIG. 4, FIG. 5, and FIG. 6, the lens barrel 2 is providedwith a first group unit 210, a second-lens-group holding member 213, athird group unit 216, a fourth-lens-group holding member 217, and afifth-lens-group holding member 218. A diaphragm unit 214 as alight-amount adjusting member at the time of photography is providedbetween the second-lens-group holding member 213 and the third groupunit 216.

The first group unit 210 is provided with a first-lens-group holdingmember 212 holding a first lens 201, and a first group base plate 211that holds the first-lens-group holding member 212 and has a barriermember that protects the first lens 201. The second-lens-group holdingmember 213 holds a second lens 202. The third group unit 216 is providedwith a third group lens holding portion 215 holding a third lens 203,and a third group base plate 216 a having a shutter member (not shown).The third group unit 216 has an image stabilization mechanism that movesthe third group lens holding portion 215 in a direction perpendicular toan optical axis during photography so as to correct an effect of acamera shake at the time of photography, etc.

The fourth-lens-group holding member 217 holds the fourth lens 204 whichconstitutes a focusing lens. The fifth-lens-group holding member 218holds a fifth lens 205 and a sixth lens 206 that constitute a fifth lensgroup, and holds the fourth-lens-group holding member 217 movable in anoptical axis direction. An optical system in the lens barrel 2 isconstituted by five lens groups as mentioned above, and a zoom operationis performed by moving the lenses of the respective groups in theoptical axis direction.

As shown in FIG. 6, the lens barrel 2 has a cover barrel 225constituting a zoom mechanism, and a sensor holder unit 219 fixed to thecover barrel 225 with screws. As shown in FIG. 4, FIG. 5, and FIG. 6,the sensor holder unit 219 holds an image pickup device 208 through asensor plate 227. An optical filter 207 is arranged at the front side(object side) of the image pickup device 208 so as to be pinched betweenthe sensor holder unit 219 and a sensor rubber 226.

Moreover, as shown in FIG. 6, the motor 401 is provided in the sensorholder unit 219.

As shown in FIG. 4 and FIG. 5, the fifth-lens-group holding member 218supports the fourth-lens-group holding member 217 so as to allow arectilinear movement in the optical axis direction. A nut portion 217 ais provided in the fourth-lens-group holding member 217. The nut portion217 a is energized by a spring 217 b toward the fourth-lens-groupholding member 217 in the optical axis direction, and is movable in theoptical axis direction together with the fourth-lens-group holdingmember 217.

The fifth-lens-group holding member 218 is provided with a drivingsource 218 a in which a screw shaft for driving the fourth-lens-groupholding member 217 is formed. Moreover, as shown in FIG. 6, a main guideshaft 218 b arranged in parallel to the optical axis and a sub guideshaft 218 c for regulating rotation are fixed to the fifth-lens-groupholding member 218 by press fit etc.

The pair of guide shafts 218 b and 218 c are respectively fitted intoguide parts 217 c and 217 d formed in the fourth-lens-group holdingmember 217 so as to be movable in the optical axis direction. When thedriving source 218 a in the fifth-lens-group holding member 218 isdriven, the screw shaft that meshes with the nut portion 217 a rotates,and the fourth-lens-group holding member 217 is driven in the opticalaxis direction. Accordingly, the fourth-lens-group holding member 217and the fifth-lens-group holding member 218 function as a focusing lensmechanism.

As shown in FIG. 4 and FIG. 5, a moving cam barrel 222 is providedaround the second-lens-group holding member 213, third group unit 216,fourth-lens-group holding member 217, and fifth-lens-group holdingmember 218. As shown in FIG. 6, three kinds of cam grooves 222 a ofwhich loci differ are formed in the periphery of the moving cam barrel222. Follower pins 213 a, 214 b, and 216 b, which are respectivelyformed in the outer peripheries of the second-lens-group holding member213, diaphragm unit 214, and third group unit 216, respectively engagewith the three kinds of cam grooves 222 a, and follow them.

Moreover, a rectilinear guide barrel 221, which regulates rotation ofthe lens groups during movement, is provided inside the moving cambarrel 222. The rectilinear guide barrel 221 and the moving cam barrel222 are connected by bayonet connection, and they move approximatelyintegrally in the optical axis direction. The moving cam barrel 222 isrelatively rotatable to the rectilinear guide barrel 221.

As shown in FIG. 6, rectilinear grooves 221 a, 221 b, and 221 cprolonged in the optical axis direction are formed in the rectilinearguide barrel 221. These rectilinear grooves 221 a, 221 b, and 221 cenable the second-lens-group holding member 213, diaphragm unit 214, andthird group unit 216 to move rectilinearly in the optical axis directionwithout rotating.

The first group base plate 211 of the first group unit 210 is arrangedaround the moving cam barrel 222. A follower-pin 211 b (see FIG. 5) isformed on the inner periphery of the first group base plate 211. Thefollower pin 211 b engages with the cam groove 222 a formed in the outerperiphery of the moving cam barrel 222 and follows the cam groove 222 a.Moreover, a linear guide groove 211 a (see FIG. 5) is formed in theinner periphery of the first group base plate 211. A guide projection221 d (see FIG. 6) formed in the rectilinear guide barrel 221 is fittedinto the linear guide groove 211 a so as to be movable in the opticalaxis direction. This allows the first group unit 210 to moverectilinearly in the optical axis direction without rotating.

According to the above-mentioned configuration, the rotation of themoving cam barrel 222 moves the first group unit 210, second-lens-groupholding member 213, diaphragm unit 214, and third group unit 216, whichfollow the moving cam barrel 222, rectilinearly in the optical axisdirection without rotating.

A decorative barrel 220 is provided around the first group unit 210together with the moving cam barrel 222. A fixed cam barrel 223 isarranged around the moving cam barrel 222. A drive barrel 224 isarranged around the fixed cam barrel 223. And the cover barrel 225 isarranged around the drive barrel 224. As shown in FIG. 4, FIG. 5, andFIG. 6, the fixed cam barrel 223 is stationarily arranged in a state tobe nipped between the cover barrel 225 and the sensor holder unit 219.

FIG. 7 is a development view showing the inner periphery of the fixedcam barrel 223. FIG. 8 is a development view showing the inner peripheryof the drive barrel 224.

As shown in FIG. 7, a cam groove 223 a and linear guide grooves 223 d 1and 223 d 2 prolonged in the optical axis direction are formed in theinner periphery of the fixed cam barrel 223. A follower pin 222 b (seeFIG. 6) of the moving cam barrel 222 engages with the cam groove 223 a.Rectilinear movement regulating parts 221 e (see FIG. 6) of therectilinear guide barrel 221 engage with the linear guide grooves 223 d1 and 223 d 2 so as to be movable in the optical axis direction.Moreover, a penetration cam 223 b is formed in the fixed cam barrel 223as a slit in the same locus as the cam groove 223 a.

As shown in FIG. 8, drive grooves 224 d prolonged in the optical axisdirection are formed in the inner periphery of the drive barrel 224. Thefollower pins 222 b of the moving cam barrel 222 engage with the drivegrooves 224 d so as to be movable. The object-side front ends (the topends in FIG. 8) of the drive grooves 224 d do not reach the object-sidefront end (the top end in FIG. 8) of the drive barrel 224. This preventsexternal stray light from entering from the object-side end of the drivebarrel 224. Moreover, the moving amount of the moving cam barrel 222 inthe optical axis direction is regulated by these drive grooves 224 d.The follower pins 222 b of the moving cam barrel 222 are arranged atpositions at predetermined intervals from the penetration cam 223 b ofthe fixed cam barrel 223 in the optical axis direction.

Accordingly, the moving cam barrel 222 moves in the optical axisdirection while following the cam groove 223 a of the fixed cam barrel223 and rotating.

The rectilinear guide barrel 221 moves in the optical axis directiontogether with the moving cam barrel 222. The rotation of the rectilinearguide barrel 221 is regulated because the rectilinear movementregulating parts 221 e fit into the linear guide grooves 223 d 1 and 223d 2 of the fixed cam barrel 223 so as to be movable. This allows therectilinear guide barrel 221 to move rectilinearly in the optical axisdirection without rotating.

A gear part 224 g (see FIG. 6) is formed on the outer periphery of thedrive barrel 224. Furthermore, a fifth-group-driving cam groove 224 a(see FIG. 6 and FIG. 8) is formed in the inner periphery of the drivebarrel 224. A follower pin 218 d (see FIG. 6) formed in the outerperiphery of the fifth-lens-group holding member 218 engages with thefifth-group-driving cam groove 224 a and follows. When the lens barrel 2is in the collapsed position, a photographing position (a wide end), anda zoom end position (a telephoto end), the follower pin 218 d moves tothe collapsed position, photographing position, and zoom end position ofthe fifth-group-driving cam groove 224 a, respectively, according to therotation of the drive barrel 224, and moves the fifth lens group in theoptical axis direction. As shown in FIG. 6 and FIG. 7, a through hole223 e prolonged in the optical axis direction is formed in the fixed cambarrel 223. The rotation of the fifth-lens-group holding member 218 isregulated because the follower pin 218 d engages with the through hole223 e.

Moreover, as shown in FIG. 6 and FIG. 8, drive-barrel-driving camgrooves 224 c are formed in the inner periphery of the drive barrel 224.Follower pins 223 j formed in the outer periphery of the fixed cambarrel 223 engage with the drive-barrel-driving cam grooves 224 c andfollow. As shown in FIG. 8, the drive-barrel-driving cam groove 224 c ofthe drive barrel 224 has two flat parts that are parallel to a rotationdirection and differ in position in the optical axis direction and alifting part that aslant connects the two flat parts. When the rotationof the drive barrel 224 moves the follower pin 223 j of the fixed cambarrel 223 to the flat part that includes the photographing position andzoom end position from the other flat part that includes the collapsedposition while following the drive-barrel-driving cam groove 224 c, thedrive barrel 224 moves to the object side in the optical axis direction.

FIG. 9A is a view describing a transmission path of the driving forcefrom the motor 401 to the driving barrel 224. FIG. 9B is an explodedperspective view of slip gears 405 and 406 shown in FIG. 9A.

As shown in FIG. 9A, the driving force of the motor 401 is slowed downand transferred from a gear (pinion) 402 attached to a drive shaft tothe gear part 224 g of the drive barrel 224 via a gear train includinggears 403 through 408. Accordingly, the drive barrel 224 rotates and thelens barrel 2 is driven in the optical axis direction. The gear trainincluding the gears 403 through 408 is equivalent to an example of thetransfer mechanism of the present invention.

The gear train including the gears 402 through 408 has the slip gear 405of large diameter as an input gear and the slip gear 406 of smalldiameter as an output gear. The slip gear 405 is supported so as to bemovable against the slip gear 406 in the axial direction.

As shown in FIG. 9B, convex portions 405 a and 406 a and concaveportions 405 b and 406 b of the same number are respectively formed inthe contact surfaces of the slip gears 405 and 406. The convex portions405 a and 406 a and the concave portions 405 b and 406 b arerespectively connected by slant portions 405 c and 406 c. A gearconnection switching mechanism (interruption mechanism) 3 drives theslip gear 405 with respect to the slip gear 406 in the axial direction.The rotation of the slip gear 405 is transferred to the slip gear 406because the slant portions 405 c and 406 c mutually come in contact.

Moreover, the rotation of the gear 407 is transferred to a gear 411through gears 409 and 410. The gear 411 is integrally formed with a discthat has a plurality of slits in the rotation direction, and therotation amount of the drive barrel 224 is detected withphotointerrupters 412 and 413 arranged across the disc.

FIG. 10A is a sectional view showing a relationship between the gearconnection switching mechanism 3 and the slip gears 405 and 406 in anelectric zoom drive state. FIG. 10B is a sectional view showing anidling state of the slip gears in FIG. 10A. FIG. 10C is a sectional viewshowing the relationship between the gear connection switching mechanism3 and the slip gears 405 and 406 in a manual zoom drive state. FIG. 10Dis a sectional view showing a pressing start state of the slip gear whenthe manual zoom drive state is switched to the electric zoom drivestate. It should be noted that the zoom drive state is switched betweenthe manual state and electric state by transferring the operation of theswitching member 102 shown in FIG. 1 to the gear connection switchingmechanism 3. Concrete configuration for transferring will be describedbelow with reference to FIG. 15A and FIG. 15B.

As shown in FIG. 10A, an energization projection 405 d of the slip gear405 comes in contact with a pressing surface 502 a formed in a back-sidelever 502 of an gear energization unit 5 in the electric zoom drivestate. The back-side lever 502 is supported by a shaft 501 so as to beslidable in the axial direction (+−Z directions) using a front-sidelever 504 as a fixed end under an energized condition toward the slipgear 406 (−Z direction) by an energization spring 503. In this state,since the slant portions 405 c and 406 c of the slip gears 405 and 406mutually come in contact, the slip gears 405 and 406 rotate integrally.Accordingly, the driving force of the motor 401 is transferred to thegear part 224 g of the drive barrel 224 via the gear train including thegears 403 through 408, and the electric zoom drive is available.

On the other hand, when the motor 401 is driven under the conditionwhere the drive barrel 224 cannot rotate in the state in FIG. 10A, loadis applied to the gear train including the gears 403 through 408. Inthis case, moving force in +Z direction occurs in the slip gear 405against the slip gear 406 due to a wedge function of the slant portions405 c and 406 c.

When the moving force in +Z direction of the slip gear 405 at this timebecomes larger than the energizing force in −Z direction of the gearenergization unit 5, the back-side lever 502 of the gear energizationunit 5 moves in +Z direction as shown in FIG. 10B. Accordingly, sincethe engagement of the convex portions 405 a and 406 a against theconcave portions 406 b and 405 b of the slip gears 405 and 406 isreleased, only the slip gear 405 races while the slip gear 406 stops.This removes the load occurred by the rotation of the motor 401.

When the load to the gear train including the gears 403 through 408 isremoved, the slip gear 405 returns to the state shown in FIG. 10A againdue to the energization force in −Z direction by the energization spring503 of the gear energization unit 5, the convex portions 405 a and 406 aand the concave portions 406 b and 405 b of the slip gears 405 and 406are engaged, and the slant portions 405 c and 406 c come in contact.When the motor 401 is continuously driven in the state where the drivebarrel 224 cannot rotate, the state shown in FIG. 10A and the stateshown in FIG. 10B are repeated alternately, and only the slip gear 405continues racing.

When there is an obstacle to the extension of the lens barrel 2, forexample, the drive barrel 224 cannot rotate. Even in such a case,breakage of a gear is prevented by racing the slip gear 405 as mentionedabove.

Moreover, the front-side lever 504 and the back-side lever 502 rotate bya predetermined angle in the manual zoom drive state so that thepressing surface 502 a of the back-side lever 502 does not come incontact with the energization projection 405 d of the slip gear 405.Accordingly, the energization to the slip gear 405 by the gearenergization unit 5 is released, and the slip gear 405 will be free inthe axial direction. In this state, even if the drive barrel 224 ismanually rotated and the gears 408, 407, and 406 rotate, the slip gear405 separates from the slip gear 406 due to the wedge function of theslant portions 405 c and 406 c as shown in FIG. 10C, and the rotation isnot transferred to the side of the motor 401.

As shown in FIG. 10C, this embodiment enables the manual zoom drive sothat the drive barrel 224 is rotatable by external force other than themotor 401 by releasing the energization to the slip gear 405 with thegear energization unit 5. Moreover, when the slip gear 405 is energizedby the gear energization unit 5 as shown in FIG. 10A, the regularelectric zoom drive is available. It should be noted that the pushingstart operation to the slip gear when the manual zoom drive state isswitched to the electric zoom drive state shown in FIG. 10D will bedescribed with reference to FIG. 15A and FIG. 15B.

FIG. 11A is an exploded perspective view showing the gear connectionswitching mechanism 3 attached to the gear box 4. FIG. 11B is anexploded perspective view showing the gear energization unit 5 thatconstitutes the gear connection switching mechanism 3 shown in FIG. 11A.

As shown in FIG. 11A, the gear connection switching mechanism 3 has thegear energization unit 5, a support member 301, a regulation shaft 302,a washer 303, a regulation-shaft energization spring 304, and an E-ring305. The gear connection switching mechanism 3 is fixed to the frontside of the gear box 4 with screws etc.

As shown in FIG. 11B, the gear energization unit 5 has the shaft 501,the back-side lever 502, the energization spring 503, and the front-sidelever 504. The gear energization unit 5 is formed as a unit by fixingwith an E-ring 505 after assembling. A D-cut portion 501 a is formed inthe shaft 501 except for the right end in FIG. 11B.

The back-side lever 502, energization spring 503, and front-side lever504 are fit to the D-cut portion 501 a in order in the axial direction.Then, the E-ring 505 is attached to a shaft groove portion 501 b whilepushing the front-side lever 504 so that the energization spring 503 iscompressed by a predetermined amount. Accordingly, the back-side lever502 is supported so as to be slidable in the axial direction of theshaft 501 against the energization force of the energization spring 503using the front-side lever 504 as a fixed end. In this supporting state,the front-side lever 504 and back-side lever 502 that have D-shapedthrough holes that engage with the D-cut portion 501 a rotate in thesame phase.

A contact portion 504 a is formed in the object side surface of thefront-side lever 504. The contact portion 504 a is projected in theaxial direction form a position decentered from the center. A grooveportion 504 b prolonged in the axial direction and a concave portion 504c prolonged in the circumferential direction are formed in the outercircumferential surface of the front-side lever 504. The concave portion504 c is shallower than the groove portion 504 b.

The energization spring 503 gives the energization force in the axialdirection to the slip gear 405 as mentioned above. Moreover, one end 503a (see FIG. 11B) of the energization spring 503 is inserted into thegroove portion 502 b formed in the back-side lever 502, and the otherend 503 b comes in contact with the front-side lever 504. Accordingly,the energization spring 503 generates charging force in a twistingdirection, and the gear energization unit 5 is energized in the rotationdirection.

Next, the behavior of the drive barrel 224 according to the manual zoomoperation will be described with reference to FIG. 12. FIG. 12A is asectional view showing the zoom operation ring 101 and lens barrel 2 inthe collapsed position. FIG. 12B is a sectional view showing the zoomoperation ring 101 and the lens barrel 2 in the photographing position(extended position).

In the state shown in FIG. 12A, the drive barrel 224 of the lens barrel2 is apart from the elastic member 116 that is fixed to the innerperiphery of the zoom operation ring 101 in the axial direction.Accordingly, even if the zoom operation ring 101 is rotationallyoperated, the rotation is not transferred to the drive barrel 224, andthe lens barrel 2 does not extend. In this embodiment, since anextending operation of the lens barrel 2 to the photographing positionfrom the collapsed position and a retracting operation to the collapsedposition from the photographing position are performed by the electriczoom drive, the rotation of the zoom operation ring 101 is preventedfrom transferring to the drive barrel 224.

Moreover, since increased load to the drive barrel 224 (lens barrel 2)due to the elastic member 116 is avoided, the smooth extending operationof the lens barrel 2 by the electric zoom drive is available, whichavoids increasing the driving current for extending or retracting thelens barrel 2. Furthermore, since the elastic member 116 does not comein contact with the drive barrel 224 in the collapsed position of thelens barrel 2, degradation of the elastic member 116 is reduced even ina case of long-term neglect under a high-temperature and high-humiditycondition.

In the state shows in FIG. 12B, the drive barrel 224 is moved to theobject side in the optical axis direction according to the extendingoperation of the lens barrel 2. Accordingly, since the elastic member116 fixed to the inner periphery of the zoom operation ring 101 engageswith the drive barrel 224 in the optical axis direction, the rotation ofthe zoom operation ring 101 is able to be transferred to the drivebarrel 224. This enables the manual zoom drive because the rotaryoperation of the zoom operation ring 101 is transferred to the drivebarrel 224 and the lens groups for varying the magnification are movedin the optical axis direction.

Next, the operation of the gear connection switching mechanism 3 will bedescribed with reference to FIG. 13A through FIG. 15B. FIG. 13A is afront view describing operations of the gear energization unit 5 and theregulation shaft 302 when the switching member 102 is operated to theelectric zoom drive. FIG. 13B is a front view describing operations ofthe gear energization unit 5 and the regulation shaft 302 when theswitching member is operated to the manual zoom drive.

The regulation shaft 302 moves in the axial direction in interlockedwith the rotational operation of the front-side lever 504 around theaxis of the shaft 501. Then, the regulation shaft 302 moves so that adrive-barrel-regulating portion 302 a is away from the lens barrel 2(FIG. 13A) in the electric zoom drive. The regulation shaft 302 moves sothat the drive-barrel-regulating portion 302 a comes near the lensbarrel 2 (FIG. 13B) in the manual zoom drive. Accordingly, the rotationrange of the drive barrel 224 is restricted.

FIG. 14A is a sectional view describing operations of the gearenergization unit 5 and the regulation shaft 302 when the switchingmember 102 is operated to the electric zoom drive. FIG. 14B is asectional view describing operations of the gear energization unit 5 andthe regulation shaft 302 when the switching member 102 is operated tothe manual zoom drive.

As shown in FIG. 14A, the washer 303 is locked by a stepped section 302b formed around the regulation shaft 302, and the peripheral edge of thewasher 303 engages with the groove portion 504 b of the front-side lever504. Accordingly, when the front-side lever 504 rotates interlocked withthe operation of the switching member 102, the regulation shaft 302slides in ±X directions along a guide hole 301 a of the support member301 against the drive barrel 224.

At the time of start-up of the camera or at the time of the electriczoom drive shown in FIG. 14A, when the lens barrel 2 is in the collapsedposition, the drive-barrel-regulating portion 302 a of the regulationshaft 302 is apart from the drive barrel 224, and the rotation range ofthe drive barrel 224 is not regulated. The energization spring 304 andE-ring 305 are attached to the regulation shaft 302. The energizationspring 304 is nipped between the support member 301 that is a fixed endand the E-ring 305 in an energized state. The energization force acts inthe +X direction in FIG. 14A so as not to regulate the rotation range ofthe drive barrel 224.

At the time of the manual zoom drive shown in FIG. 14B, since thedrive-barrel-regulating portion 302 a of the regulation shaft 302 isfitted into an engaging groove 224 b formed in the drive barrel 224, therotation range of the drive barrel 224 is restricted within a range ofthe engaging groove 224 b. The engaging groove 224 b is formed so as toprevent the lens barrel 2 from retracting to the collapsed position fromthe photographing position, and the engagement (FIG. 12B) of the elasticmember 116 with the drive barrel 224 is guaranteed within the rotationrange. Accordingly, a user is able to perform the manual zoom drivewithin the range in which the zoom operation is available withoutconsidering the rotation range of the drive barrel 224.

FIG. 15A is a perspective view describing operations of the gearenergization unit 5 and the regulation shaft 302 when the switchingmember 102 is operated to the electric zoom drive. FIG. 15B is aperspective view describing operations of the gear energization unit 5and the regulation shaft 302 when the switching member 102 is operatedto the manual zoom drive.

The switching member 102 is provided in the front of the storage portionof the motor 401 so as to be slidable. A projection 102 a that slidesalong the upper surface of the storage portion is integrally formed atthe back side of the switching member 102. The projection 102 a comes incontact with the contact portion 504 a formed in the front-side lever504 of the gear energization unit 5, and the slide of the switchingmember 102 is transferred as the rotation of the gear energization unit5. The gear energization unit 5 is energized in the clockwise directionin FIG. 15A by the energization force of the energization spring 503 andregulation-shaft energization spring 304. Accordingly, the contactportion 504 a always comes in contact with the projection 102 a.

In the state shown in FIG. 15A, the pressing surface 502 a of theback-side lever 502 comes in contact with the front end of theenergization projection 405 d of the slip gear 405 as the input gear.The energization force of the energization spring 503 is applied in thedirection that the pressing surface 502 a presses down the energizationprojection 405 d. Accordingly, the convex parts 405 a and 406 a and theconcave portions 406 b and 405 b of the slip gears 405 and 406 areengaged as shown in FIG. 10A, which enables the electric zoom drive bythe motor 401.

In the state shown in FIG. 15B, the contact portion 504 a of thefront-side lever 504 is pushed by the projection 102 a of the switchingmember 102 that is operated to slide in the rightward direction in thedrawing, and the gear energization unit 5 rotates in thecounterclockwise direction around the shaft 501. Accordingly, thepressing operation by the pressing surface 502 a of the back-side lever502 to the energization projection 405 d of the slip gear 405 isreleased as shown in FIG. 10C. In this state, the rotation transmissionpath from the motor 401 to the drive barrel 224 is intercepted, and themanual zoom drive by the rotary operation of the zoom operation ring 101becomes available.

As shown in FIG. 15A and FIG. 15B, the contact portion 504 a of thefront-side lever 504 is in contact with the projection 102 a of theswitching member 102 in both of the electric zoom drive and manual zoomdrive. Accordingly, backlash of the switching member 102 is eliminated.

The operation amount of the switching member 102 is determined on thebasis of the required rotational amount of the back-side lever 502 andthe depth of the engaging groove 224 b of the drive barrel 224. That is,when the lens barrel 2 is in the collapsed position and when theelectric zoom drive is selected as shown in FIG. 15A and FIG. 14A, theengaging groove 224 b is not located at the position facing to theregulation shaft 302, and the regulation shaft 302 faces an outercircumferential surface 224 f of the drive barrel 224. Then, when theregulation shaft 302 comes in contact with the outer circumferentialsurface of the drive barrel 224, the movement of the regulation shaft302 is regulated, and the operation toward the manual zoom drive of theswitching member 102 connected to the regulation shaft 302 via thefront-side lever 504 is also regulated. Accordingly, the camera alwaysstarts up by the electric zoom drive, and an operation mistake isprevented.

In the first embodiment, since the range of the engaging groove 224 b ofthe drive barrel 224 in the rotation direction is defined between a wideend and a telephoto of optical zoom, the switching member 102 cannot beswitched to the manual zoom drive when the lens barrel 2 is in thecollapsed position. Accordingly, when the power is turned ON, theextending operation of the lens barrel 2 is certainly performedelectrically, which shortens the time required to reach thephotographing position as compared with a case where the extendingoperation is performed manually.

Moreover, when the switching member 102 is switched to the electric zoomdrive from the manual zoom drive, the back-side lever 502 rotates whilepushing down the energization projection 405 d of the slip gear 405because the gear energization unit 5 is always energized by theenergization spring 503 in the clockwise direction in FIG. 15A. As shownin FIG. 10D, a slope is formed in the energization projection 405 d ofthe slip gear 405, and a slope 502 c is formed also in the back-sidelever 502 at the opposite side. This facilitates the pushing-down of theenergization projection 405 d by the back-side lever 502, and enablesthe slip gear 405 to engage with the slip gear 406 in a state where thephases are matched.

The mechanism that pushes down the slip gear 405 by the rotation of theback-side lever 502 using the slopes miniaturizes and thins the cameraby simplifying the mechanism and by saving the space, as compared with amechanism that pushes the slip gear 405 in the axial direction.

As described above, in the first embodiment, while the lens barrel 2 iselectrically shifted to a photographing area from the collapsed positionin a non-photographing area, the drive barrel 224 of the lens barrel 2engages with the elastic member 116 on the inner periphery of the zoomoperation ring 101. This enables to transfer the rotation of the zoomoperation ring 101 to the drive barrel 224 via the elastic member 116,and enables to perform the electric zoom drive or the manual zoom driveby operating the switching member 102 in this state.

Accordingly, the manual zoom drive and electric zoom drive are switchedwith the simple mechanism, which enables to miniaturize and thin thecamera 1 in addition to the lens barrel 2. Moreover, since the rotationof the zoom operation ring 101 is transferred to the drive barrel 224via the elastic member 116, generation of time lag between a rotaryoperation of the zoom operation ring 101 and lens drive is prevented.

FIG. 16 is a sectional view schematically showing a state where a lensbarrel of a digital camera as a second embodiment of an image pickupapparatus equipped with a lens driving device of the present inventionis in a collapsed position. FIG. 17 is a sectional view schematicallyshowing a state where the lens barrel of the digital camera shown inFIG. 16 is in a photographing position.

The digital camera of the second embodiment is constituted by mountingthe lens barrel 10 in the front side (object side) of a camera body 6.As shown in FIG. 16 and FIG. 17, the lens barrel 10 includes a zoom lensthat changes photographing magnification by moving a plurality of lenses11 and 12 in an optical axis direction. The lenses 11 and 12 constitutea photographing optical system. The lens barrel 10 is provided with afirst group barrel unit 10 a, an intermediate barrel unit 10 b, and afixed barrel unit 10 c.

An image pickup device 14 is held by a sensor holder 20 in the camerabody 6 at a rear side of the lens barrel 10. An image is formed on theimage pickup device 14 by an object light flux passing through thelenses 11 and 12. Moreover, an operation ring 7 is provided around afront end of the lens barrel 10 so as to allow a rotary operation and amovement in the optical axis direction. A plurality of pins 7 a that areprojected inwardly in the radial direction are formed on the innerperiphery of the operation ring 7 at nearly regular intervals in thecircumferential direction. It should be noted that detailed members,such as cam grooves and cam followers that move the lenses 11 and 12 inthe optical axis direction, a shutter device, and a focusing lens, areomitted in FIG. 16 and FIG. 17.

The first group barrel unit 10 a has a first group holder 41 holding thefirst lens 11, and a decorative cap 42. The intermediate barrel unit 10b has an inside rectilinear barrel 31, a rotating cam barrel 32, and aninner cover barrel 33. The second group holder 43 holding the secondlens 12 is provided inside the rotating cam barrel 32. The fixed barrelunit 10 c has a fixed barrel 21, a drive barrel 22, and an outside coverbarrel 23. The outside cover barrel 23 is equivalent to an example ofthe barrel member of the present invention. The outside cover barrel 23is fixed to the fixed barrel 21. A plurality of convex parts 23 a thatare projected inwardly in the radial direction are formed on the innerperiphery of the outside cover barrel 23.

A gear part 22 a is provided in the drive barrel 22, and driving forceof a motor 51 is transferred to the gear part 22 a through a gear trainincluding gears 52 and 53. Accordingly, the drive barrel 22 is rotated,and the rotation of the drive barrel 22 is transferred to the rotatingcam barrel 32 that cam-engages with the drive barrel 22. Accordingly,the second group holder 43 moves in the optical axis direction togetherwith the rotating cam barrel 32 and the inside rectilinear barrel 31while the rotation of the second group holder 43 is regulated by theinside rectilinear barrel 31. The first group holder 41 that cam-engageswith the inside rectilinear barrel 31 also moves in the optical axisdirection while the rotation is regulated in the same manner. Pinengagement portions 22 b and a bayonet engaging groove 22 c are formedin the outer periphery of the drive barrel 22. The pins 7 a of theoperation ring 7 engage with the pin engagement portion 22 b. The convexparts 23 a of the outside cover barrel 23 engage with the bayonetengaging groove 22 c.

FIG. 18 is a sectional view showing the operation ring 7. FIG. 19 is anexploded perspective view showing the operation ring 7, the drive barrel22, and the outside cover barrel 23.

Although the groove portion 2 b formed in the inner periphery of theoperation ring 7 in the circumferential direction and a locking lever 61that is provided in the camera body 6 and engages with the grooveportion 2 b are described in FIG. 18, these are mechanisms needed in athird embodiment mentioned later, and these are not indispensable in thesecond embodiment.

When the locking lever 61 engages with the groove portion 2 b, theposition of the operation ring 7 in the optical axis direction isregulated at the position for electric zoom. The locking lever 61 isprovided in the inner periphery of the operation ring 7 so as to bemovable in the radial direction by a driving source (not shown). Itshould be noted that the locking lever 61 may be driven by the drivingsource provided separately from the motor 51, or may be driveninterlocked with the zoom drive of the lens barrel 10 by the motor 51.

As shown in FIG. 19, the bayonet engaging groove 22 c has an axialgroove 22 c 1 prolonged in the axial direction towards the rear sidefrom the front end of the drive barrel 22 and a circumferential groove22 c 2 prolonged in the circumferential direction from the rear end ofthe axial groove 22 c 1. The front end of the circumferential groove 22c 2 is formed so that the width in the axial direction becomes narrow inits front end (see FIG. 20A).

When the drive barrel 22 is rotated relatively to the outside coverbarrel 23 under the condition where the convex part 23 a of the outsidecover barrel 23 is inserted to the rear end of the axial groove 22 c 1of the drive barrel 22, the convex part 23 a engages with the narrowwidth portion at the front end of the circumferential groove 22 c 2.Accordingly, the drive barrel 22 is inserted into the outside coverbarrel 23. The convex part 23 a is equivalent to an example of theregulation part of the present invention.

The pin engagement portion 22 b has a plurality of ridge walls 22 b 1and a plurality of projected walls 22 b 2. The ridge walls 22 b 1 areformed in the outer periphery end at the object side of the drive barrel22 at a predetermined interval in the circumferential direction. Theprojected walls 22 b 2 are projected towards the rear side of the drivebarrel 22 from the ridge walls 22 b 1. The projected walls 22 b 2 arearranged at nearly regular intervals in the circumferential direction ofthe drive barrel 22. The front end of the projected wall 22 b 2 isformed in a tapered shape of which the width becomes narrower graduallytowards the rear side of the drive barrel 22. When the operation ring 7is moved in the optical axis direction, the pin 7 a engages with a spacebetween the projected walls 22 b 2 that are adjacent in thecircumferential direction so that the pin 7 a is detachable in therotation direction.

Since the operation ring 7 and the drive barrel 22 rotate integrally inthe state where the pins 7 a of the operation ring 7 engage with the pinengagement portions 22 b of the drive barrel 22 in the rotationdirection, the rotary operation of the operation ring 7 rotates thedrive barrel 22.

Next, the relationship between the pins 7 a of the operation ring 7, thegear part 22 a of the drive barrel 22, the pin engagement portions 22 b,the bayonet engaging groove 22 c, the convex part 23 a of the outsidecover barrel 23, and the gear 53 will be described with reference toFIG. 20A through FIG. 24B.

FIG. 20A is a developed view showing an outer periphery of the drivebarrel 22 in a state where the power of the camera is OFF and the lensbarrel 10 is in the collapsed position. As shown in FIG. 20A, the convexpart 23 a of the outside cover barrel 23 is located in a collapsedposition S in the bayonet engaging groove 22 c of the drive barrel 22. Awide position W on which the convex part 23 a is located in the widestate of the lens barrel and a telephoto position T on which the convexpart 23 a is located in the telephoto state of the lens barrel are shownin FIG. 20A. Moreover, alternate long-and-short dash lines A showpositions (A positions) of the convex part 23 a and the pin 7 a in theelectric zoom drive. Alternate long-and-short dash lines M showpositions (M positions) of the convex part 23 a and the pin 7 a in themanual zoom drive.

Then, the convex part 23 a of the outside cover barrel 23 engages withthe narrow width portion of the circumferential groove 22 c 2 of thebayonet engaging groove 22 c within the section between the collapsedposition S and just before the wide position W in order to regulate theposition of the drive barrel 22 and to maintain the engagement of thegear part 22 a of the drive barrel 22 with the gear 53.

Two grooves 22 d that are prolonged in the circumferential direction andare mutually separated in the optical axis direction are formed in theside surface of the drive barrel 22. When the drive barrel 22 moves inthe optical axis direction, engagement of a clicking plate 62 with eachof the two grooves 22 d gives a click operation feeling such that thedrive barrel 22 stops each of the electric zoom drive position andmanual zoom drive position to the operation ring 7 via the drive barrel22.

In the state in FIG. 20A, since the pin 7 a of the operation ring 7 isin the A-position and does not engage with the pin engagement portion 22b of the drive barrel 22, the rotary operation of the operation ring 7does not rotate the drive barrel 22. In the second embodiment, the lensbarrel 10 is driven electrically because the gear part 22 a of the drivebarrel 22 meshes with the gear 53 during a process from the collapsedposition S where the power of the camera is OFF to the wide position W.At this time, the click board 62 engages with the groove 22 d of thedrive barrel 22 at the lower side in the drawing, and accordingly, thedrive barrel 22 is kept so as not to move in the optical axis directioncarelessly.

FIG. 20B is a developed view showing the outer periphery of the drivebarrel in a state where the lens barrel 10 is moved to the wide positionW by the electric zoom drive. FIG. 20B shows the state of the drivebarrel 22 that was rotated in an arrow direction (the rightwarddirection in the drawing) from the state in FIG. 20A by the electriczoom drive. In the photographing state between the wide position W shownin FIG. 20B and the telephoto position T, the convex part 23 a of theoutside cover barrel 23 engages with a wide width portion in thecircumferential groove 22 c 2 of the bayonet engaging groove 22 c inorder to enable the movement of the drive barrel 22 in the optical axisdirection. Accordingly, although the convex part 23 a is in theA-position after the lens barrel 10 moves to the wide position W, thedrive barrel 22 is movable in the optical axis direction.

FIG. 21A and FIG. 21B are developed views showing the outer periphery ofthe drive barrel 22 in states before and after the lens barrel 10 in thewide position is shifted to the manual zoom operation from the electriczoom operation, When shifting to the manual zoom operation from theelectric zoom operation, an operator operates the operation ring 7 fromthe state in FIG. 20B toward the extension side (lower side in thedrawings) in the optical axis direction first. Accordingly, the pin 7 aof the operation ring 7 engages with the pin engagement portion 22 b ofthe drive barrel 22 as shown in FIG. 21A, and the drive barrel 22becomes rotatable together with the operation ring 7.

In this state, when the operation ring 7 is further operated toward theextension side in the optical axis direction, the pin 7 a of theoperation ring 7 pushes the pin engagement portion 22 b of the drivebarrel 22, and the drive barrel 22 moves toward the extension side inthe optical axis direction together with the operation ring 7. Themovement of the drive barrel 22 releases the engagement of the gear part22 a with the gear 53 as shown in FIG. 21B, and the convex part 23 a isarranged in the M-position. At this time, the click board 62 engageswith the groove 22 d of the drive barrel 22 at the upper side in thedrawing, and accordingly, the drive barrel 22 is kept so as not to movein the optical axis direction carelessly.

In the state shown in FIG. 21B, the connection between the motor 51 andthe drive barrel 22 is released, and the manual rotary operation of theoperation ring 7 makes the drive barrel 22 rotate together with theoperation ring 7, which enables the manual zoom operation. FIG. 22 is asectional view schematically showing the camera in the state in FIG.21A. FIG. 23 is a sectional view schematically showing the camera in thestate in FIG. 21B.

FIG. 21C is a developed view showing the outer periphery of the drivebarrel 22 in a state where the lens barrel 10 is moved to the telephotoposition by the manual zoom operation. In addition to the illustratedpositions, the drive barrel 22 is able to be stopped in an arbitraryintermediate position between the wide position W (FIG. 21B) and thetelephoto position T (FIG. 21C).

FIG. 24A and FIG. 24B are developed views showing the outer periphery ofthe drive barrel 22 in states before and after the lens barrel 10 in thetelephoto position is shifted to the electric zoom operation from themanual zoom operation, First, when an operator operates the operationring 7 toward the retraction side (the upper side in the drawing) in theoptical axis direction from the state in FIG. 21C first, the pin 7 a ofthe operation ring 7 goes away from the pin engagement portion 22 b ofthe drive barrel 22 as shown in FIG. 24A. Accordingly, the rotaryoperation of the operation ring 7 does not rotate the drive barrel 22.

At this time, the pin 7 a of the operation ring 7 comes in contact witha side wall 22 f that is opposite to the pin engagement portion 22 b ofthe drive barrel 22 in the optical axis direction. Accordingly, when theoperation ring 7 is further operated toward the retraction side in theoptical axis direction, the pin 7 a of the operation ring 7 pushes theside wall 22 f of the drive barrel 22, and the drive barrel 22 movestoward the retraction side in the optical axis direction together withthe operation ring 7 as shown in FIG. 24B. Accordingly, the gear 53meshes with the gear part 22 a, and the convex part 23 a is arranged inthe A-position. Accordingly, the driving force of the motor 51 istransferred to the gear part 22 a via the gear 53 to rotate the drivebarrel 22, which enables the electric zoom operation.

It should be noted that the change to the manual zoom operation from theelectric zoom operation, otherwise the change to the electric zoomoperation from the manual zoom operation are available also in anintermediate position other than the wide position W and telephotoposition T. Moreover, it is necessary to engage the convex part 23 awith the narrow width portion in the circumferential groove 22 c 2 ofthe bayonet engaging groove 22 c in the section between the wideposition W and the collapsed position S, as shown in FIG. 20A. Then, itis necessary to arrange the convex part 23 a in the A-position as shownin FIG. 24B in order to engage the convex part 23 a with the narrowwidth portion in the circumferential groove 22 c 2. Accordingly, whenthe power of the camera is turned OFF in the state allowing the manualzoom operation, it is necessary to once change to the electric zoomoperation before performing the collapsing operation.

Next, the operation of the camera will be described with reference toFIG. 25, FIG. 26A, and FIG. 26B. It should be noted that the processesin FIG. 25 through FIG. 27 are performed so that a CPU of a controlcircuit in the camera body 6 develops programs stored in a ROM to a RAMand performs the program (not shown).

Moreover, the position of the operation ring 7 in the optical axisdirection shall be detected by a ring position detection unit (notshown) corresponding to the position of the pin 7 a. The position of thedrive barrel 22 against the convex part 23 a in the optical axisdirection shall be detected by a drive-barrel-position-detecting unit(not shown). A photo reflector is used as the ring position detectionunit and the drive-barrel-position-detecting unit, for example.

Furthermore, in the second embodiment, the engagement of the gear 53 atthe side of the motor 51 with the gear part 22 a of the drive barrel 22can be released in an arbitrary position in the section between the wideposition W and telephoto position T of the lens barrel 10 so that theoperation ring 7 can be manually rotated freely with the drive barrel22. Accordingly, when the position of the lens barrel 10 in the opticalaxis direction is detected on the basis of the rotation-output pulse ofthe motor 51, inconsistency will occur. Thus, the position of the lensbarrel 10 in the optical axis direction is detected on the basis of adetection signal of a device that detects the position of the lensbarrel 10 relative to a home position in addition to the pulse signal ofthe motor 51.

FIG. 25 is a flowchart describing camera operations from a power OFFstate to a photographing-ready state in the digital camera.

When the camera power is turned ON in step S101, the process proceeds tostep S102, and the control circuit determines whether the operation ring7 is in the electric zoom position on the basis of the detection resultof the ring position detection unit (not shown). Then, when theoperation ring 7 is in the electric zoom position, the process proceedsto step S104. When the operation ring 7 is not in the electric zoomposition (the operation ring 7 is pulled), the process proceeds to stepS103.

The control circuit notifies a user to move the operation ring 7 to theelectric zoom position by displaying a message on a display unit (notshown) of the camera body 6 or by outputting a voice messages etc. inthe step S103, and returns the process to the step S102. In the stepS104, the motor 51 is driven to start moving the lens barrel in theextending direction, and the process proceeds to step S105.

In the step S105, the control circuit determines whether the lens barrel10 reached the wide position on the basis of the pulse signal of themotor 51, etc. The process proceeds to step S108 if reached. Otherwise,the process proceeds to step 106.

In the step S106, the control circuit determines whether the operationring 7 is maintained in the electric zoom position during the lensbarrel extension drive until the lens barrel 10 reaches the wideposition. Then, when the operation ring 7 is maintained in the electriczoom position, the control circuit returns the process to the step S105.When the operation ring 7 is not in the electric zoom position, thecontrol circuit proceeds with the process to step S107.

The control circuit once stops driving the motor 51 in the step S107,notifies the user to move the operation ring 7 to the electric zoomposition in the step S103, and returns the process to the step S102. Theoperations in the steps S107 and S103 aim to maintain the electric zoomoperation by preventing the engagement with the gear 53 from releasing,when the operation ring 7 is pulled in the manual zoom position. Thecontrol circuit stops driving the motor 51 in the wide position in thestep S108, shifts to the photographing-ready state in step S109, andfinishes the process.

FIG. 26A and FIG. 26B are flowcharts describing a process for switchingthe zoom operation mode between the electric zoom operation and themanual zoom operation under the photographing-ready state. It should benoted that three states are assumed in the section between the wideposition and telephoto position where the switching process isallowable. In the first state, both the pin 7 a of the operation ring 7and the convex part 23 a are in the A-positions (FIG. 20B). In thesecond state, the pin 7 a is in the M-position and the convex part 23 ais in the A-position (FIG. 21A). In the third state, both the pin 7 aand the convex part 23 a are in the A-positions (FIG. 21B). The processin FIG. 26A and FIG. 26B enables the electric zoom operation in thefirst state in FIG. 20B, enables the manual zoom operation in the thirdstate in FIG. 21B, and urges to select one of the electric and manualzoom operations in the second state in FIG. 21A by determining thepositions of the pin 7 a and the convex part 23 a.

When the camera shifted to the photographing-ready state in step S201,the control circuit determines whether the pin 7 a was moved to theM-position from the A-position according to the operation of theoperation ring 7 in step S202 on the basis of the detection result ofthe ring position detection unit (not shown). Then, when the pin 7 a wasnot moved to the M-position, the control circuit proceeds with theprocess to step S203, continues the electric zoom operation, and returnsthe process to the step S202. When the pin 7 a was moved to theM-position, the process proceeds to step S204.

The control circuit stops the electric zoom drive by stopping drivingthe motor 51 in the step S204, and proceeds with the process to stepS205. In the step S205, the control circuit determines whether themovement of the drive barrel 22 in the optical axis direction due to theoperation of the operation ring 7 moved the convex part 23 a to theM-position from the A-position on the basis of the detection result ofthe drive-barrel-position-detecting unit (not shown). Then, when theconvex part 23 a was moved to the M-position, the control circuitproceeds with the process to step S209. When the convex part 23 a wasnot moved to the M-position, the control circuit proceeds with theprocess to step S206. The control circuit maintains the stopped state ofthe motor 51 and allows the manual zoom drive in the step S209, andproceeds with the process to step S210. Accordingly, the electric zoomoperation is switched to the manual zoom operation.

In the step S210, the control circuit determines whether the operationof the operation ring 7 moved the pin 7 a to the A-position from theM-position on the basis of the detection result of the ring positiondetection unit (not shown). When the pin 7 a was not moved to theA-position, the process returns to the step S209. When it is determinedthat the pin 7 a moved to the A-position, the process proceeds to stepS211. In the step S211, the control circuit determines whether themovement of the drive barrel 22 in the optical axis direction due to theoperation of the operation ring 7 moved the convex part 23 a to theA-position from the M-position on the basis of the detection result ofthe drive-barrel-position-detecting unit (not shown). Then, when theconvex part 23 a was moved to the A-position from the M-position, thecontrol circuit proceeds with the process to the step S203 and shifts tothe electric zoom drive. When the convex part 23 a was not moved to theA-position, the control circuit proceeds with the process to step S212.

The control circuit notifies the user to move the operation ring 7 tothe electric zoom position or the manual zoom position by displaying amessage on a display unit (not shown) of the camera body 6 or byoutputting a voice message, etc. in the step S212, and proceeds with theprocess to step S213.

In the step S213, the control circuit determines whether the operationof the operation ring 7 moved the convex part 23 a to the A-position onthe basis of the detection result of the drive-barrel-position-detectingunit (not shown). Then, when the convex part 23 a was moved to theA-position, the control circuit proceeds with the process to step S203.When the convex part 23 a was not moved to the A-position, the controlcircuit proceeds with the process to step S214. In the step S214, thecontrol circuit determines whether the operation of the operation ring 7moved the pin 7 a to the M-position from the A-position on the basis ofthe detection result of the ring position detection unit (not shown).When the movement to the M-position is detected, the process returns tothe step S209, and the manual zoom drive continue. When the pin 7 a wasnot moved to the M-position, the process returns to the step S212 torepeat notification.

On the other hand, the control circuit notifies the user to move theoperation ring 7 to the electric zoom position or the manual zoomposition by displaying a message on a display unit (not shown) of thecamera body 6 or by outputting a voice message, etc. in the step S206,and proceeds with the process to the step S207.

In the step S207, the control circuit determines whether it was detectedthat the operation of the operation ring 7 moved the convex part 23 a tothe M-position. When the movement to the M-position was detected, theprocess proceeds to the step S209 to shift to the manual zoom drive.Otherwise, the process proceeds to step S208. In the step S208, thecontrol circuit determines whether the operation of the operation ring 7moved the pin 7 a to the A-position from the M-position on the basis ofthe detection result of the ring position detection unit (not shown).When the movement to the A-position is detected, the process proceeds tothe step S203 to shift to the electric zoom drive. When the pin 7 a wasnot moved to the A-position, the process returns to the step S206 torepeat notification.

The processes in the steps S205 through S208 and the steps S210 and S211aim to prevent a halfway state where both the electric and manual zoomoperations become impossible when the zoom mode is switched between theelectric zoom operation and manual zoom operation.

FIG. 27 is a flowchart describing a process from the photographing-readystate to the power OFF state of the camera.

When the power of the camera was turned OFF in the photographing-readystate in step S301, the control circuit determines whether the operationring 7 is in the electric zoom position in step S302 on the basis of thedetection result of the ring position detection unit (not shown). Then,when the operation ring 7 is in the electric zoom position, the processproceeds to step S304. When the operation ring 7 is not in the electriczoom position (the operation ring 7 is pulled), the process proceeds tostep S303.

The control circuit notifies the user to move the operation ring 7 tothe electric zoom position by displaying a message on a display unit(not shown) of the camera body 6 or by outputting a voice message, etc.in the step S303, and returns the process to the step S302. In the stepS304, the motor 51 is driven to start moving the lens barrel in theretracting direction, and the process proceeds to step S305.

In the step S305, the control circuit determines whether the lens barrel10 reached the collapsed position on the basis of the pulse signal ofthe motor 51, etc. When the lens barrel 10 reached the collapsedposition, the control circuit proceeds with the process to step S308,turns OFF the power of the camera after stopping driving the motor 51,and finishes the process. When the lens barrel 10 does not reach thecollapsed position, the process proceeds to step S306.

In the step S306, the control circuit determines whether the operationring 7 is maintained in the electric zoom position during the lensbarrel retracting drive until the lens barrel 10 reaches the collapsedposition. Then, when the operation ring 7 is maintained in the electriczoom position, the control circuit returns the process to the step S305.When the operation ring 7 is not in the electric zoom position, thecontrol circuit proceeds with the process to step S307.

The control circuit once stops driving the motor 51 in the step S307,notifies the user to move the operation ring 7 to the electric zoomposition in the step S303, and returns the process to the step S302. Theoperations in the steps S307 and S303 aim to maintain the electric zoomoperation by preventing the engagement with the gear 53 from releasing,when the operation ring 7 is pulled in the manual zoom position.

As described above, the second embodiment enables to switch the electriczoom operation and the manual zoom operation by the operation ring 7 thelens barrel with the simple mechanism, and improves operability of themanual operation of the operation ring.

Next, a digital camera according to a third embodiment of an imagepickup apparatus equipped with a lens driving device of the inventionwill be described with reference to FIG. 28 to FIG. 29. It should benoted that duplicated sections with respect to the above-mentionedsecond embodiment will be described by diverting the figures and thesigns.

The third embodiment employs the mechanism shown in FIG. 18 thatregulates the movement of the operation ring 7 in the optical axisdirection by engaging the locking lever 61 provided in the camera body 6with the groove portion 7 b of the operation ring 7 when the operationring 7 is in the electric zoom position. When the locking lever 61 isused, the determination about whether the operation ring 7 is in theelectric zoom position in each of the steps S102 and S106 in FIG. 25 andthe step S306 in FIG. 27 becomes unnecessary.

FIG. 28 is a flowchart describing camera operations from the power OFFof the digital camera to the photographing-ready state.

When the power of the camera turns ON in step S401, the control circuitdrives the motor 51 to start moving the lens barrel in the extendingdirection in step S402, and proceeds with the process to step S403. Inthe step S403, the control circuit determines whether the lens barrel 10reached to the wide position on the basis of the pulse signal of themotor 51, etc. When reached, the process proceeds to step S404.Otherwise, the process returns to the step S402.

The control circuit stops driving the motor 51 in the wide position inthe step S404, and proceeds with the process to step S405. In step S405,The control circuit drives the locking lever 61 so as to go away fromthe groove portion 7 b to release regulation of movement of theoperation ring 7 in the optical axis direction in the step S405, shiftsto the photographing-ready state in step S406, and finishes the process.

FIG. 29 is a flowchart describing a process from the photographing-readystate to the power OFF of the camera.

When the power of the camera was turned OFF in the photographing-readystate in step S501, the control circuit determines whether the operationring 7 is in the electric zoom position in step S502 on the basis of thedetection result of the ring position detection unit (not shown). Then,when the operation ring 7 is in the electric zoom position, the processproceeds to step S504. When the operation ring 7 is not in the electriczoom position (the operation ring 7 is pulled), the process proceeds tostep S503.

The control circuit notifies the user to move the operation ring 7 tothe electric zoom position by displaying a message on a display unit(not shown) of the camera body 6 or by outputting a voice messages etc.in the step S503, and returns the process to the step S502. The controlcircuit drives the locking lever 61 so as to engage with the grooveportion 7 b to regulate the movement of the operation ring 7 in theoptical axis direction in the step S504, and proceeds with the processto step S505.

In the step S505, the motor 51 is driven to start moving the lens barrelin the retracting direction, and the process proceeds to step S506. Inthe step S506, the control circuit determines whether the lens barrel 10reached the collapsed position on the of the pulse signal of the motor51, etc. When reached, the process proceeds to step S507. Otherwise, theprocess returns to the step 505. The control circuit stops driving themotor 51 in the collapsed position to turn OFF the power of the camerain the step S507, and finishes the process. The other configurations andoperational effects are the same as that of the above-mentioned secondembodiment.

In the above-mentioned embodiments, although the manual/electricswitching about lens drive for zooming were described as an example, thepresent invention is not limited to the embodiments. The presentinvention is applicable to a manual/electric switching about lens drivefor focusing. Moreover, although the above-mentioned embodimentsexemplified a digital camera as an image pickup apparatus, the presentinvention is not limited to this. The present invention is applicable toa digital video camera and other image pickup apparatus. Furthermore,the above-mentioned second embodiment uses the pin engagement portion 22b that is formed by the walls having the tapered forms. Alternatively,the pin 7 a may be frictionally engaged with an elastic member, such assponge.

Other Embodiments

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Applications No.2015-162686, filed Aug. 20, 2015 and No. 2016-020746, filed Feb. 5,2016, which are hereby incorporated by reference herein in theirentireties.

What is claimed is:
 1. A lens barrel mounted on an image pickupapparatus that supports an operation member rotatably, the lens barrelcomprising: a drive barrel configured to engage with a lens holdingmember that holds a lens and to drive the lens holding member in anoptical axis direction by moving in the optical axis direction whilerotating; a motor configured to transfer rotation to said drive barrelthrough a transfer mechanism; a switching mechanism configured to switchlens drive between electric lens drive that drives the lens holdingmember in the optical axis direction by transferring rotation of themotor to said drive barrel, and manual lens drive that drives the lensholding member in the optical axis direction by transferring rotation ofthe operation member to said drive barrel via an elastic member thatrotates together with the operation member, according to a user'soperation; and an interruption mechanism configured to interrupt atransfer path that transfers the rotation from the motor to said drivebarrel via the transfer mechanism when the lens drive is switched to themanual lens drive by said switching mechanism in a state where saiddrive barrel engages with the elastic member, wherein said drive barrelengages with the elastic member while shifting from a non-photographingarea to a photographing area in the optical axis direction so as toallow the rotation of the operation member.
 2. The lens barrel accordingto claim 1, wherein the elastic member is fixed to an inner periphery ofthe operation member.
 3. The lens barrel according to claim 1, whereinsaid drive barrel moves in the optical axis direction while rotatingfrom the non-photographing area until engaging with the elastic member.4. The lens barrel according to claim 1, wherein the operation member isa zoom operation member.
 5. An image pickup apparatus comprising: anoperation member configured to be supported by the image pickupapparatus so as to allow a rotary operation; An elastic memberconfigured to be arranged in an inner periphery of said operationmember, and to rotate together with said operation member; and a zoomlens barrel configured to change photographing magnification by moving aplurality of lens groups included in an optical axis direction, the zoomlens barrel comprising: a drive barrel configured to engage with a lensholding member that holds a lens group and to drive the lens holdingmember in an optical axis direction by moving in the optical axisdirection while rotating; a motor configured to transfer rotation tosaid drive barrel through a transfer mechanism; a switching mechanismconfigured to switch lens drive between electric lens drive that drivesthe lens holding member in the optical axis direction by transferringrotation of said motor to said drive barrel, and manual lens drive thatdrives the lens holding member in the optical axis direction bytransferring rotation of the operation member to said drive barrel viathe elastic member that rotates together with the operation member,according to a user's operation; and an interruption mechanismconfigured to interrupt a transfer path that transfers the rotation fromthe motor to said drive barrel via the transfer mechanism when the lensdrive is switched to the manual lens drive by said switching mechanismin a state where said drive barrel engages with the elastic member,wherein said drive barrel engages with the elastic member while shiftingfrom a non-photographing area to a photographing area in the opticalaxis direction so as to allow the rotation of the operation member.